Conventional video recording systems are typically tape-based (i.e., video cassette recorders (VCRs) using VHS tape). Such systems do not compress audio and video or provide random access storage. Conventional video recording systems also do not provide content analysis. The lack of random access prevents the systems from accessing a playlist generated from post processed statistics. In particular, since the playlist has to be known ahead of time for playback but can only be recorded after the commercial has been recorded to the media.
Some conventional VCRs provide commercial skip features. However, such systems need a second pass to go through the tape and mark the detected commercials. Conventional VCRs operate in the analog domain and use only audio mute and black frames to detect commercials. Therefore, commercial skip on tape is not a seamless experience for the user. In particular, the tape is accelerated through the commercial then decelerated and brought back to smooth, stable realtime playback with proper tension at the end of the advertisement.
Even if there were and alternate storage device in a tape-based system (e.g., the playlist were stored to flash), the mechanics of accelerating the tape through the commercial, tracking timing during the fast forward, decelerating and recovering video synchronization smoothly renders the feature considerably more expensive and less useful than disk-based systems.
Users find the commercial skip feature of HDD recorders (also known as DVRs, PVRs or time-shifters) to be a compelling feature. Typical half-hour television programs contain 6 to 8 minutes of commercials, so the user can watch a one hour program in 44 to 48 minutes if it is originally recorded to a HDD. Identifying and skipping a commercial, however, requires user intervention, which is undesirable. Moreover, the user must watch enough of the commercial to recognize it as an advertisement and not a return to the desired programming.
In order for a user to skip commercials in a digital recording system, the user must view, detect and provide (e.g., via the remote control) input to the system to prompt scene removal. Such a configuration uses additional time, disks space and activity on part of the user. Some conventional recording systems use a manual 27 second commercial skip. However, this is also an approximate, fixed distance rather than the proper duration of the advertisement. Other conventional automatic commercial skip features (e.g., Replay TVs/SonicBlue) have the disadvantage of (a) using only video statistics and/or (b) being built from discrete systems of audio encoders, video encoders and/or separate processors.
It would be desirable to provide an audio/video recorder with automatic commercial advancement detection and/or skip features that may (i) use both audio and video characteristics, (ii) be integrated as a system without adding computational complexity, cost, latency, or memory and (iii) be more accurate than conventional approaches by using encoding statistics (e.g., DC motion characteristics, etc.).